A decade ago I wrote a story called "Shooting at Firemen," inspired by some events in my childhood. Because one of the characters resembled my sister Diane Chamberlain I sent her a copy before submitting it for publication, to make sure she was okay with it. She was, but besides being my sibling she is also a bestselling novelist, so naturally she had a few suggestions.
And the one that I remember best was this: I had written a story about a twelve-year-old boy set in 1967 and never mentioned music.
Well, duh. I put in some references to hits of the day and sold the story to Alfred Hitchcock's Mystery Magazine (July/August 2015).
But since then I have always tried to remember the advice offered by some writer (not, I believe, my sis): Your story should connect to all five senses.
Sure, you will describe what your characters are seeing. But have they heard any sounds besides dialog? Music, car noise, bird calls? What do they taste or smell? When they sit down, how does the fabric of that chair feel?
A few months ago I set a story in the Peloponnese and so I found myself trying to remember what the Lousios Valley smelled like. (In brief: woodsy.)
Of course, you can put in too much detail about this (as you can with any other element) of the story, but a little of it can make things feel more real to the reader.
And let's not stop with five senses, shall we?
No, I am not referring to the sixth sense, unless we are about to enter a Bruce Willis movie (And don't get me started on non-paranormal fiction in which a person miraculously and accurately senses that they are being watched.)
But here are some other senses I found listed on various websites:
Balance.
Hunger.
Movement.
Pain.
Pressure.
Proprioception. (Where your body parts are in relation to other body parts. It is how you can touch type. It is also what cops are testing when they ask a possibly intoxicated person to touch their nose.)
Thermoception. (Heat and cold.)
Thirst.
Time.
You probably include many of these in your fiction without giving them a second thought. But when you are trying to add depth to a story, you might run down this list and learn more about what your characters are feeling.